Such a torsion spring bar axle is known through French Pat. No. 2 123 291. There the torsion rod and the carrier tube have a square cross-section, the side of the strand-shaped rubber bodies facing inside being adjacent to the plane outer wall of the torsion rod and the side facing outside being adjacent to the bevelled inner edge of the carrier tube. It is known from practice that such torsion spring axles do not have substantial dampening characteristics, as the rubber bodies are merely subject to compression or squeezing deformation.
The steel torsion rod protruding through the hollow torsion rod connects the wheel swing levers to one another and is supported rotationally rigid in the central section by a wall interspersing the carrier tube.
In cooperation the rubber bodies and the steel torsion rod of the rubber spring axle result in a lightly steeper spring characteristic with higher load resistance, but it acts practically without dampening.